25-Jun-24 - 07:24 PM

Thermal Circle Text - Thermal Circle 17

Written by Hayden Daley - 13 October 2008.
  Welcome to this edition, in this edition we will have a detailed look at F5J competition, the electric thermal soaring class that uses high powered electric motors in soaring competition and the F3K class of competition, hand launched sailplanes are at the end of this edition

The object of F5J is to provide man on man competition in an RC thermal duration event, with qualifying rounds; and the pilots with the best times are awarded a place in the fly-off to compete for the top places in the event. This edition contains an overview of the rules and how the event is contested.

To fit into the rules the competing model must fit within these guidelines. Maximum surface area of 150dm2, maximum flying weight 5kg and a maximum loading of 75g/dm2. The model cannot have arresting devices, skegs, etc to assist with landing are not allowed. The radio used must be able to operate with other units in 20khz spacing between legally approved channels, so 36mhz in Australia and radio certification will be required to adhere to this rule. 2.4 ghz is also accepted for transmission in these events. Telemetry is not allowed, varios etc are not permitted.

The pilot may enter two aircraft in the competiton and can combine parts to make a third model if possible as long as the model falls within the rules as provided. The pilot must enter two channels at the start of the event to allow for fair man on man competition. All ballast added to the model must be carried internally, inside the model.

There is no limitations on the motor types that can be used in F5J competition. The pilot must operate his transmitter by himself however each competitor is allowed one helper per round. The flying site must have reasonably even terrain to minimize the possibility of slope or wave soaring (F3J also has this rule). The flying site will have appropriate landing spots, one for each competitor and the landing spots must be equipped with a measuring device. It is forbidden for any part of the model to land or come to rest in the safety area. Any breach of the safety rules will result in 100 point deduction from the pilots final score.

For an event to have a result there will be a minimum of four or more qualification flights with a ten minute working time. There will be two final flights with a fifteen minute working time and the competitor will be allowed two attempts at each official flight. The competitor will be allowed time for model repair if an accident or incident occurs during the contest. In case of a second flight the second score will count as the result for that round. Reflights are allowed if the model is involved in a mid air collision or the pilot was involved in an event that interrupted his flight due to no fault of himself.

The following disqualification rules apply in F5J. The flight is cancelled and a zero score will be recorded if the model does not conform to the contest rules. In the case of apparent and intentional cheating the pilot may be disqualified from the contest. The contest director can inspect any model at any time. The flight is cancelled and issued a zero score if the model loses any part or parts during an official flight except in the case of a mid air collision in this case a reflight will be awarded. When landing the model may lose parts, this is permitted as the model is not flying at this stage; however if a model loses parts in landing more than seventy five meters away the flight is cancelled and awarded a zero score. The flight is recorded as a zero score if any other person flys the model during a contest flight.

A minimum of five, preferably more competitors will contest each round. The rounds are to be arranged to allow pilots to fly against as many different pilots as possible. Competitors are to be allowed at least five minutes of preparation time before working time begins in a round. The organizers must announce the beginning of working time with an audible signal or visual signals. The ending of working time must also be announced by signal. The contest director will designate a launching area and all competitors must launch from this area. Any model launched before the official working time is started must land and relaunched within the actual working time. A zero will be awarded for that round if these rules are not followed.

There is no limit on motor run and the competitor may run his engine twice only during the flight. If the pilot decides to use a second attempt on his flight during the working time the contest director must be advised..A landing bonus will be awarded if the pilot land in the designated area within the rules and a maximum landing bonus will be 100 additional points. The pilot with the highest aggregate score will be awarded 1000 points as the heat winner; the rest of the pilots will be index scored against the winners 1000 points as used in most soaring competitions The completion of the qualifying rounds a minimum of six and a maximum of ten pilots will make the fly off judged by qualifying scores. The fly off working time is fifteen minutes. The results of the event will be decided by these final fly off.

F5J is a welcome addition to thermal soaring competition. The MAAA has allowed for this event during the once yearly nationals allowing for a national champion in this event. For older thermal soaring competitors this allows for an event that does not require the collection of winch lines; a great assistance for older people. This event will grow in time and look forward to interesting and exciting electric sailplanes as this event developes and more contests are run; and the rules are further refined by the regulatory groups and the FAI. We will now take a detailed look at F3K competitive soaring and the rules used in this event. F3K is the FAI designation for the handlaunched class of RC thermal soaring sailplanes. The models used in theses events are widely available from Australian suppliers and some people also construct the models they used to compete.

The MAAA hosts F3K at the Nationals allowing for an Australian champion in this class of soaring. This text contains the major rules used in these events including events held in Australia.

To comply with the rules an F3K model is to have a maximum wingspan of 1500mm and a maximum weight of 600gm. The nose radius must exceed 5mm. The model must be hand launched and controlled by RC equipment. The pilot can exchange parts with other models. The pilot must provide two frequencies on entering to allow the pilot to compete with as many other pilots as possible.

The flying field must be large enough for the amount of pilots competing and should not provide slope or wave lift if possible. The contest director will assign launch and landing areas. Any landing not in the designated area will receive a zero score. The landing is accepted as legal if any part touches the designated landing area or if the pilot catches the model the landing will be accepted if caught in the landing area. The flight is measured from the moment the model is launched until the moment the model is landed. The flight time is official if all these rules are adhered to, not complying with the rules results in a zero score.

F3K is flown in rounds, as provided in other FAI RC soaring classes. The working time is ten minutes. The start and end of working time are to be announced by an audible signal. The heats must contain as many pilots as possible and with a minimum of seven competitors. The heat results are to be scored to 1000 points per heat, the winner of the heat will achieve a final score of 1000 points. The pilots are allowed 2 minutes preparation time, and the beginning of the two minutes must be announced by the contest director. Radios are allowed to be switched on during the preparation time. For the event to be allowed a result at least five rounds must be flown. The organizers will decide which tasks are to be flown.

F3K is the most affordable of sailplane competitions to compete in. Model Flight and the Airstrike company sell F3K models and there are many choices. These models use modern construction techniques and most models are all composite. The average wingloading is around 3.5 oz to 4oz. Light wingloadings mean the models are very light and require very little thermal activity to start climbing; and these models can be slope soared in very light lift. F3K models also allow for great competitive soaring practice for the die hard competition pilots wishing to hone his low level soaring techniques.

Hayden Daley. October 2008..

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